One of Oregon’s largest native carnivores, the controversial gray wolf, can have far-reaching impacts on plant life in the habitats it occupies, according to an Oregon State University professor.

On Tuesday evening, Worthy Brewing will host a presentation by Bill Ripple, professor at OSU’s College of Forestry in Corvallis, about the impact wolves have on aspen groves and other plants, and on the role displaced large carnivores play more broadly in the ecosystems they occupy.

“I really think it’s all tied together in a larger ecological and environmental sense,” Ripple said Friday.

Ripple began looking at the impact of wolves more than two decades ago, after visiting Yellowstone National Park in 1997. He noted that aspen trees had stopped growing back after gray wolves were hunted to extinction in the area. When wolves were reintroduced to the park in the mid-1990s and began expanding through the habitat, aspen began to return and grow larger, according to Ripple.

He later published a paper linking the decline in wolf populations to overbrowsing of young aspen stands by elk in the area, arguing that wolves play a vital role in the ecosystem by managing elk numbers within their territory. From there, Ripple expanded the research to other displaced predators in other national parks, including Olympic, Zion and Yosemite national parks. He continued to study gray wolves in Canada’s Jasper National Park.

“We consistently found that, when the predator was removed, the plants didn’t flourish,” Ripple said.

While Ripple said he has not studied Oregon’s wolf population, the species has grabbed headlines across the state over the past decade. Gray wolves once roamed across much of Oregon, but encroachment by humans caused wolf populations to decline in the first half of the 20th century.

For much of the second half of the century, there were no established wolf packs in Oregon.

Wolves, descended from those reintroduced in Idaho and Wyoming in the 1990s, began to return to Oregon in the mid-2000s. As of 2017, 124 wolves were confirmed to be living in Oregon, mostly in the northeastern corner of the state.

Worthy founder Roger Worthington discovered Ripple through a paper, titled “World Scientists’ Warning to Humanity: A Second Notice,” according to Grant Tandy, observatory manager for the Worthy Garden Club, an environmental nonprofit based at Worthy Brewing.

The paper, co-authored by Ripple and published in 2017, looks back on a call for environmental action by scientists 25 years earlier, noting that humanity has not made significant progress in solving its environmental challenges. Tandy said Worthington was inspired by the paper, and the nonprofit donated $50,000 to Ripple’s ongoing research. In part, Worthy is hosting Ripple to let him articulate what makes his research important.

“It’s a huge paper, but it’s abstract if you don’t meet the person,” Tandy said.

The event will begin at 7 p.m. at Worthy Brewing’s Hop Mahal, near the back of the building at 495 NE Bellevue Road, in Bend. Tandy said the space can accommodate up to 150 people; he said he expects it to fill up for the talk.